It doesn’t matter which opioid is included in an epidural infusion in terms of either analgesia or side effects.  (Image source: Thinkstock)

It doesn’t matter which opioid is included in an epidural infusion in terms of either analgesia or side effects. (Image source: Thinkstock)

Opioids are commonly added to epidural infusions because of the additional analgesic properties provided by neuraxial opioids. Is there a “best” opioid to provide 24 hours of analgesia after surgery?

Dr. James Paul, Department of Anesthesia, McMaster University, Hamilton, Ontario, and colleagues performed a meta-analysis of trials that compared perioperative epidural opioid infusions for postoperative analgesia. The results of this analysis are featured in this month’s issue of Anesthesia & Analgesia in the article titled “What Epidural Opioid Results in the Best Analgesia Outcomes and Fewest Side Effects After Surgery?: A Meta-Analysis of Randomized Controlled Trials.

Twenty-four studies met the authors’ inclusion criteria. These studies included approximately 1,500 patients. When fentanyl was compared to sufentanil, there was no difference in pain scores. There were no differences when epidural morphine was compared to epidural sufentanil, oxycodone, or hydromorphone. Higher PONV was seen with morphine compared with fentanyl, however (absolute risk reduction of 10%). No statistically significant difference in terms of pruritus was observed. The incidence of respiratory depression and hypotension was low no matter which opioid was used. The incidence of sedation was similar between groups. Opioid consumption was slightly lower in the morphine group than the fentanyl group.

Limitations include the fact that not all of the studies were blinded, that only English language studies were included, and that not every opioid was compared. The data do not suggest that it matters which opioid is included in an epidural infusion in terms of either analgesia or side effects.